Disposable anesthesia device

ABSTRACT

A disposable anesthesia device that is completely assembled and ready to use in administering anesthetic gas from a source thereof to a patient. The device provides a closed circuit connectable with a conventional anesthesia machine and consisting of a face mask, a rebreathing bag, a canister containing granular carbon dioxide absorbing material, flexible inhalation and exhalation tubes connecting the face mask with the canister and the rebreathing bag, and flap-like inhalation and exhalation valves, all parts of the device, with the exception of the granular canister contents, but including the valves, being molded or otherwise made of plastic and hence economically disposable after one use thereof to preclude the danger of patient cross contamination.

United States Patent 1191 Wise et al.

11 1 1 3,820,959 June 28, 1974 DISPOSABLE ANESTHESIA DEVICE [75] Inventors: Lewis Abraham Wise; John E.

Grimm, both of Santa Monica, Calif.

Assignee: Will Ross, Inc., Milwaukee, Wis.

Filed: Feb. 14, 1973 Appl. No.: 332,316

Related US Application Data Division of Ser. No. 85,201, Oct. 29, 1970, Pat. No. 3,721,238

[52] US. Cl 23/284, 128/188, 23/288 R,

[5 6] References Cited UNlTED STATES'PATENTS 8/l945 Larson 210/286 6/ l 958 Hay. lO/l97l Doering 128/19] R l28/l9l R FOREIGN PATENTS OR APPLICATIONS 525,699 195 4 Delgium 210 2 Primary Examiner-Richard A. Gaudet Assistant Examiner-Henry J. Recla [57] ABSTRACT A disposable anesthesia device that is completely assembled and ready to use in administering anesthetic gas from a source thereof to a patient. The device provides a closed circuit connectable with a conventional anesthesia machine and consisting of a face mask, a rebreathing bag, a canister containing granular carbon dioxide absorbing material, flexible inhalation and exhalation tubes connecting the face mask with the canister and the rebreathing bag, and flap-like inhalation and exhalation valves, all parts of the device, with the exception of the granular canister contents, but including the valves, being molded or otherwise made of plastic and hence economically disposable after one use thereof to preclude the danger of patient cross contamination.

3 Claims, 6 Drawing Figures 1 IIISIQSABLE ANESTHESTA DEVICE This invention is a division of the copending application Ser. No. 85,201 filed Oct. 29, 1970, now'US. Pat. No. 3,721,238.

This invention relates generally to anesthesia apparatus and, more particularly, to that part thereof which may be considered its delivery system, by which anesthetic gases coming from an anesthesia machine in predetermined volume and mixture, are fed to the patient under the control of either an anesthesiologist or an anesthetist. Hereinafter, for sake of brevity, where the term anesthetist is used it will be understood to include anesthesiologist as well. This delivery system forms a closed circuit or circle, as it is referred to by anesthetists, and consists of a canister containing granular carbon dioxide absorbing material, a face mask, a rebreathing bag, flexible inhalation and exhalation tubes connecting the face mask with the canister and the rebreathing bag, check valves that control flow to and from the mask, and an adjustable pressure relief valve bywhich the anesthetist can control the pressure in the system.

Closed circuit anesthesia devices are of course not new in concept, but heretofore they have been relatively expensive, costing between three and four hundred dollars. More significantly, though, they were intended for and designed to be reused. This confronted hospitals with a very disconcerting dilemma. If a reusable system or apparatus was used on a patient with a communicable respiratory disease, the entire apparatus could become infected. Subsequent use of the infected apparatus on other patients could, and often did, infect those patients.

The likelihood of cross infection from unsterile and contaminated circle systems was understood and appreciated by the hospitals, but itwas most difficult to clean and sterilize the available reusable systems. They had to be completely taken apart and washed thoroughly with germicidal solutions just to clean them. This was a time consuming bother,-and sterilization of the reusable equipment was an even greater problem.

The materials rubber and metal of which the conventional reusable circle systems were made, were deleteriously affected if steam pressure autoclaves were used, and if ethylene oxide gas sterilizers were employed the long aeration time required to get rid of the highly toxic ethylene oxide gas that was absorbed into the rubber parts forced hospitals to have a very large number of the reusable circle systems on hand or run the risk of patient cross contamination.

The obvious answer to this dilemma was an anesthetic delivery apparatus that would be inexpensive enough to be entirely disposable, but heretofore no such thing existed.

It is the purpose and object of this invention to fill that need, and to do so significant innovations have been made in the component parts of the system. As a result of these improvements, all of the components of the entire system except the granular carbon dioxide absorbing material which fills the canister are relatively inexpensive molded or otherwise formed plastic parts. The net result is a fully assembled, highly efficient closed circuit system that not only is completely reliable and easy to use, and readily disposable, but also exceptionally attractive in appearance, as

2 evidenced by 115. Design Pat. No. Des. 215,982, issued Nov. 11, 1969, to the instant applicants.

With these observations and objectives in mind, the manner in which the invention achieves its purpose will be appreciated from the following description and the accompanying drawings, which exemplify the invention, it being understood that such changes in the specitic apparatus disclosed herein may be made as come within the scope of the appended] claims.

The accompanying drawings illustrate a physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

FIG. 1 is a perspective view of the complete anesthetic device of this invention;

. FIG. 2 is a perspective view of the canister which contains the carbon dioxide absorbing material, and its cover shown lifted from the canister;

FIG. 3 is a sectional view through the canister on the plane of the line 3-3 in FIG. 2;

FIG. 4 is a detail sectional view through the inhalation port structure of the canister, said view being taken on the plane of line 4-4 in FIG. I;

FIG. 5 is a detail sectional view through the exhalation port structure of the canister, taken on the plane of the line 55 in FIG. l; and

FIG. 6 is a plan view'of the valve disc employed in both the inhalation and exhalation valves.

Referring to the accompanying drawings, in which like numerals designate like parts throughout the several views, the numeral 5 designates the face mask of the closed circuit or circle device of this invention and which is connected by flexible inhalation and exhalation tubes 6 and 7, respectively, with a rebreathing bag 8 and a canister 9 containing granular carbon dioxide absorbing material 10.

The face mask is a cupped plastic molding having a suitably shaped and cushioned edge 11 defining its face-engaging opening, and a cylindrical rearwardly projecting nipple l2 onto which a head strap plate 13 is fitted, to provide for the attachment of straps (not shown) by which the mask may he held in place on a patient. An elbow 14, which is inserted into the nipple I2, and a Y-shaped coupling l5 connect the mask with the inhalation and exhalation tubes. The elbow and the Y fitting are molded plastic parts.

The canister 9 comprises a tub-shaped molded plastic open-topped container 16 with a straight slightly in wardly sloping side wall, and a cover 17, also a plastic molded part, closing the top of the container. A partition wall 1l8 extending diametrically across the interior of the container divides the same into two compartments that are connected only at the bottom through an opening 19 in the partition wall. The upper edge 20 of the partition wall extends horizontally straight across the container at an elevation somewhat above the top edge of the container, but slopes downwardly at its ends as at 21. As seen in FIG. 2, the opening 19 in the partition wall is the space between legs 19 at the side edges of the partition wall. These legs engage the bottom of the container and thus coact with the cover 17 to hold the partition wall against vertical displacement.

Both compartments of the canister are filled with the granular carbon dioxide absorbing material 10,, and to hold this material in place and prevent internal shifting thereof which, if permitted, might objectionably pulverize some of the material, perforated inner covers 22 are tightly fitted into the tops of the container compartments. The perforations of these inner covers are smaller than the particle size of the absorbent material 10.

The cover 17, which will be referred to as an outer cover to distinguish it from the perforated inner covers 22, has a downwardly opening groove 23 extending diametrically thereacross to snugly receive the upper edge portion of the partition wall 18 including its downwardly sloping ends 21. Accordingly, the spaces in the upper portions of the two canister compartments above the perforated inner covers are sealed from one another except by passage through the interstices between the particles of the granular carbon dioxide absorbing material.

The underside of the outer cover 17 also has spacer ribs 24 depending therefrom to engage and firmly hold the perforated inner covers in place. These spacer ribs extend at right angles to the groove 23 and hence do not interfere with open communication of the spaces above the perforated inner covers with open bottomed hollow protuberances 25 and 26 which rise from the top of the outer cover 17 at opposite sides of the groove 23.

Being open bottomed, the hollow protuberances have unrestricted communication with the spaces above the perforated inner covers 22 and form part of inlet and outlet ports, designated generally by the numerals 27 and 28, respectively, through which the canister is connected with the inhalation and exhalation tubes. The inlet port 27, in addition to the protuberance 25, comprises short and long tubular stubs 29 and 30, respectively, extending in diametrically opposite directions from the hollow protuberance 25. The long stub 30 provides an inlet for fresh gas which may be fed thereto from a conventional anesthesia gas machine in any suitable manner.

Mounted on the shorter stub 29 is a T-coupling 31, the stem of which has the rebreathing bag 8 attached thereto. The T-coupling is mounted on the stub 29 by fitting one end of its head onto the stub. The opposite end of the head of the T receives a short rigid tube 32 which projects from and is secured to the adjacent end of the flexible inhalation tube 6. As shown in FIG. 4, the bore 33 through the head of the T is slightly enlarged at its end'into which the stub 29 fits, to, provide a locating shoulder 34 that bears against the end of the stub, and at the opposite end of the bore 33 there is another shoulder 35 which not only limits insertion of the tube 32 into the bore, but coacts with the end of the tube to hold a valve member 36 in place.

The valve member 36 is a disc of thin air-impervious pliable plastic material of a diameter very slightly smaller than the bore 33 outwardly of the shoulder 35, so that the valve disc may be easily inserted into the bore and against the shoulder. At a short distance in from its periphery, the disc 36 has an arcuate slit 37 that extends concentrically along nearly all of the circumference of the disc, to define a central flap 38 and an encircling ring 39 hingedly connected at a small localized zone 40. The radial width of the ring 39 is less than the width of the shoulder 35 but at least as great as the wall thickness of the coupling tube 32. Hence, with the parts assembled, the ring 39 is tightly clamped between opposing shoulders, one of which is provided by the end of the tube 32 and the other being the shoul- 4 der 35 upon which the flap 38 seats. A very simple but highly reliable inhalation valve is thus provided to open upon inspiration and close upon expiration.

A similar exhalation valve is located adjacent to the protuberance 26 but, in this case, the shoulders between which the ring 39 of the valve disc is clamped are provided by an outwardly facing rather narrow shoulder 41 in the bore of a short tubular stub 42 that projects from the side of the protuberance 26, and the end of a short rigid coupling tube 43 that is secured to and projects from the adjacent end of the flexible exhalation tube 7. As shown in FIG. 5, the wall thickness of the coupling tube 43 at least at the end thereof received in the tubular stub 42 is greater than the radial width of the ring 39 and hence provides a seat against which the flap 38 bears in the closed condition of the exhalation valve.

As will be readily apparent, the inhalation and exhalation valves, being entirely selfcontained and devoid of springs, are the epitome of simplicity but, more significantly, the manner in which they are oriented makes them completely reliable and instantly responsive to inspiration and expiration of a patient undergoing anesthesia.

The most important advantage of the anesthesia device of this invention stems from the fact that the shoulders between which the valve discs are confined are vertically disposed when the canister is in its normal position of use; and the discs are so placed that their hinge portions40 are at the top. The flaps thus hang freely in their closed or seated positions, and since they are practically weightless, they respond to the most minute pressure differential. The anesthetist can therefore proceed with utmost assurance that, at even the lowest level of breathi g. Only cleaned air from which carbon dioxide has been removed by its passage through the contents of the canister, and fresh gas coming directly from the gas machine can enter the patients lungs.

During use, the rebreathing bag, which is as much a part of the closed circuit as any other portion thereof, enables the anesthetist to assist the patient in his breathing. Since the pressure is uniform in all parts of the closed circuit, the pressure in the rebreathing bag is exactly the same as the pressure in the patients lungs. This then provides the anesthetist with the indication needed to tell him whether or not to assist the patients breathing by rhythmically squeezing the bag. His feel of the bag will also indicate to him if the pressure in the system is correct.

To enable regulation of the pressure in the system, an adjustable pressure relief or pop off valve 45 is provided. This valve is mounted on the protuberance 26, the top wall 46 of which has a hole 47 encircled by an upstanding rim 48, the top of which provides a seat for a light button-like valve disc 49. The valve disc is guided for movement to and from its seat by a cylindrical valve cage 50 that rises from the top wall 46 of the protuberance and circumscribes the rim 48.

The lower portion of the valve cage has a plurality of openings 51 through which its interior is communicated with atmosphere. The upper portion of the cage is externally threaded, as at 52, to adjustably mount a cap 53 that has a top wall-54 with a scalloped edge 55 to facilitate turning the cap, and a downwardly projecting central stem 56 to overlie and limit the extent the valve disc can lift off its seat. Hence, by screwing the tion can beembodied in forms other than as herein disclosed for purposes of illustration.

comprising:

cap further onto or off the valve cage, the pressure in the system can be regulated.

The button-like valve disc 49 is formed of light foam or cellular plastic material, preferably polyurethane foam, with a veneer 49 of thin non-adherent sheet 5 plastic on its opposite flat faces, Mylar being especially well adapted for the purpose.

With the exception of the granular carbon dioxide Those skilled in the art will appreciate that the inven- The invention is defined by the following claims.

We claim:

1. A canister for a closed circuit anesthesia device,

A. an open topped container having joined bottom and side walls;

B. a partition in the container having side edges in contact with opposite side wall portions and a bottom edge portion and means associated with said partition to space said bottom edge from the bottom wall of the container so that said partition divides the container into two side-by-side compartments communicated at the bottom,

the partition having an upper edge portion extending across the open top of the container;

C. granular carbon dioxide absorbing material filling both compartments of the container to a level short of the upper edge of the partition;

D. a perforated inner cover closing the top of each compartment finnly engaged with the top of the granular material to confine the same against shiftmg;

E. an outer cover across the top of the container and fixed thereto, said outer cover having a downwardly opening slot in which the upper edge portion of the partition wall is snugly received, so that the spaces between the perforated inner covers and the top cover are closed off from one another;

F. hollow protuberances rising from the outer cover, one over each of said spaces above the perforated inner covers and communicated therewith; and

G. tubular stubs projecting from said hollow protuberances to which coupling members may be attached to connect the canister in said closed circuit.

2. The canister of claim 1, wherein said partition wall has spaced apart legs projecting from the bottom thereof to engage the bottom of the container and thus coact with the outer cover to hold the partition against vertical displacement,

the space between said legs providing the only communication between the side-by-side compartments.

3. The canister of claim 1, wherein all of said recited elements except the granular material are molded plastic parts,

so that the canister is disposable. 

2. The canister of claim 1, wherein said partition wall has spaced apart legs projecting from the bottom thereof to engage the bottom of the container and thus coact with the outer cover to hold the partition against vertical displacement, the space between said legs providing the only communication between the side-by-side compartments.
 3. The canister of claim 1, wherein all of said recited elements except the granular material are molded plastic parts, so that the canister is disposable. 